Growing MEMS Markets by Rethinking Manufacturing

BSAC Manufacturing Workshop:

Growing MEMS Markets
by Rethinking Manufacturing

By Paula Doe, SEMI

Whatever the specific
predictions for a vast Internet of Things, or the future market for a trillion sensors,
it’s clear the world is moving towards new possibilities of using more sensors
in more places to collect more data to do more things. The interesting question
is what’s needed to take advantage of these kinds of potential opportunities,
with proposed solutions ranging from open platforms and more integrated
functionality, to printed sensors and batch assembly processes.

Leading
MEMS technologists at the recent Berkeley Sensor and Actuator Center research
overview meeting argued that enabling big future growth of sensors would
require disruptive lower-cost manufacturing technologies— with more open
platforms and more system thinking, to open development to a much wider range
of creative minds to develop more applications.

Fast-growing
demand for MEMS sensors is already turning the niche into a much more mature
industry, moving towards stable high-volume production capability, tinier and
lower cost devices, ever improving performance, easy-to-integrate functions, and
even faster time-to-market. But
potentially huge future sensor applications will require more innovative manufacturing
technologies and designs to reduce costs, as well as more focus on adding value
beyond just the component, by things like integrating more sensor data and more
intelligence to add functions to systems.

Major
growth of markets for complex technological systems has often been enabled by de-coupling
design from manufacturing, argued Kaigham (Ken) Gabriel, now moved from DARPA
to Corporate VP for advanced technology at Motorola Mobility. “This means a
conscious throwing away of performance at the component level to shift the
design emphasis to the system, and to handling complexity,” he explained. Most
obvious example is the IC industry, where the fabless model expanded the
numbers of chip designers from thousands to tens of thousands and greatly
increased the diversity of ideas and new products. But he also argued the same
trends were evident across electronic systems, where the separation of
assemblers from higher-level programming languages helped expand the development
of new functions. A more recent example may be the wider availability of
affordable and better quality 3D printing tools, which have opened that
technology platform to such unexpected uses as the 30,000 3D printed faces with
different expressions that animators made for Norman for the movie ParaNorman. Gabriel
argued that scaling up accessible platforms to produce large networks of
sensors would similarly enable many as yet unimagined applications, noting French
World War I hero Marshal Foch’s famous opinion that airplanes were interesting
toys, but of no military value. “That’s why it’s important to scale up production—we
create new things by building,” noted Gabriel.

A
major TerraSwarm research project, funded by DARPA and Semiconductor Research
Corp. (SRC) industry partners, aims to build such an open common platform for
wireless sensor networks. “The goal is an applications development platform to
unleash lots of creative minds to figure out what to do with sensor networks,”
explained UC Berkeley professor Edward Lee, noting how the Apple apps platform similarly
enabled a range of applications unimagined just a few years ago. He argued that
wireless sensor networks had yet to developed as projected because they so far
worked only as closed systems.

The attractiveness of competing in 100x larger markets using proprietary design as competitive advantage, as opposed to using both proprietary process and design as now, may encourage companies to cooperate to develop standard MEMS manufacturing processes, argued Janusz Bryzek, VP for MEMS and sensing solutions at Fairchild Semiconductor. While mainstream MEMS analysts don’t see these gigantic markets looming yet for huge networks of low cost sensors, given current technology and cost constraints, big growth in technology markets has often come from applications that were not predicted. Companies like Bosch, Hewlett-Packard and Intel are all now looking at applications of sensor data from large networks of sensors, for everything from oil field monitoring to mobile context awareness to home health monitoring.

But
to enable such wide adoption of sensor data, MEMS makers will need to find ways
to significantly reduce development time to months instead of years, and find
ways to use more standard production processes, to continue to reduce sensor
size and cost. When inevitably asked about the impossibility of standard
processes for MEMS, Bryzek pointed out that past standard processes such as
Sandia’s Summit V and Memscap’s MUMPS had limited capability for high-volume
applications, but InvenSense’s more recent open high-volume capacitive inertial
sensor process had made several runs of multi-project wafers with designs from
a broad range of organizations. And the
main families of capacitive sensors may be settling around some common
approaches. Other panelists noted that
MEMS sensors were probably now good enough for most applications, and the value
was clearly moving from the sensor to the system in any case.

Some
of the ultra-high volume, ultra-low cost sensor applications will need a new
manufacturing paradigm, such as roll-to-roll 3D printing, Bryzek suggests. And
accelerating the development time will need a roadmap. He is organizing a
workshop at Stanford University this fall to identify the likely future ultra
high-volume sensor applications, the future technology needed to produce them,
and potential pre-competitive mechanisms such as consortiums to fund that work.

Enabling
sensor networks will certainly require some low-cost wireless transmission of
signals, and some low-cost solutions for assembling lots of tiny die. Alien
Technology CTO and founder John Stephen Smith reported the company’s tiny, low-cost
passive RF ID tags suggest a possible solution. The tags are currently being
used for live inventory control of clothing at Macy’s, J.C. Penney’s and
Walmart, as well as in railroad ties to track age and need for replacement, and
in strip mines to track which areas particular ores come from. The company has
reduced the cost of these simple RF ID tags to pennies, in part by reducing the
silicon die size to a mere 0.5mm x 0.5mm, making handling and assembling the
tiny units onto the antenna/substrate the most expensive part of production. To
significantly reduce the cost of traditional pick and place assembly, Alien
turned to KOH-etching the backside of the die into a faceted shape, and then
using microfluidics to flow the units into matching depressions across the
substrate. Smith says this efficient
batch process can reduce assembly costs from $0.01 to $0.001 per unit.

One
impressive example of an innovative sensor, and how integrating data from
multiple sensors can add real value, is Proteus Digital Health’s progress
towards getting early warning of impending health crises by analyzing data from
its pill sensors with that of sleep patterns from an accelerometer. Its sensor
uses MEMS-like planar processes to add copper and magnesium layers to a tiny
chip, which are activated by stomach acid when swallowed, to send a signal to a
receiver in a bandaid-like patch worn by the user. An accelerometer in the
patch meanwhile records the user’s activity. Both signals are sent to a smart
phone or computer for analysis. “Now the data from the patch becomes
information,” said CTO and co-founder Mark Zdeblick, showing charts of skipped
doses and highly disrupted sleep patterns that typically predict the onset of problems
for those with mental illness. He notes that most people with real
medication-dependent diseases don’t mind wearing the patch because the downside
is so much worse. The company is exploring how the mobile phone could help remind
or reward people to take their medication, by texting reminders, by notifying
friends or relatives, or by offering little rewards like a video of the day’s
soccer highlights or a donation of a dose to help save someone’s life in
Africa.

And
the power of integrating more functions by smarter processing looks to continue
to spur MEMS growth, now interestingly spreading even to MEMS timing,
traditionally a more discrete feature than, say, inertial sensing “Customers
are now asking for functions, such as multiple clocks, or a sleep/wake up
feature,” reported Mark Lutz, VP and co-founder of SiTime. “MEMS timing has typically been a replacement
market for a decent established technology, but adding new functions really
opens things up….The newest MEMS timing results out-perform quartz, and they
will continue to improve, but now it’s about what else can we do with this.” He
also noted the possibility of integrating the resonators in a single
system-in-package with a microcontroller or a front end modem instead of as
separately packaged components.